I've been reading the Dynamics That Underlie Creative Thinking (first chapter is at www.dmi.org) by Jeff Mauzy and Richard Harriman. 
They break the creative process into 4 dynamics. 

Motivation, 
Curiosity and Fear, 
Breaking and Making Connections and 
Evaluation. 

Creative thinking is defined as the ability to make mental connections between unrelated matters. Motivation is the desire to change. The greater the level of emotional investment the greater the motivation. They talk about the best source of motivation being intrinsic, interior motivation.... the desire to change, to express oneself, to explore. As the authors say..."the intrinsic process is associated with passion and even fun, and a high level of creativity." 

When you are motivated and moved to action, the next step in the search is for useful information.

"Curiosity is an aspect of the search for knowledge and sense, it leads people to experiment with their environment: it leads them to unplanned discoveries. They go on to say, "Often people who are motivated and curious and who break  loose of inhibitions reach into new experiences and uncover knowledge that is beyond the sensible, anticipatory scenario." The fear factor... "As someone searches curiously through the new experience for unimagined knowledge, they reach into the unknown". It is disconcerting to stretch your comfort level and risk failure. But this is what the artist goes through, this search for the unknown and definition of one self, in every genuine work of art they create. And to be fair "each person has a different tolerance for risk" The solution for keeping fear in check "lies in such a strong intrinsic belief in the work that you can commit yourself beyond the point of possible discouragement. You have to fall passionately in love with your project and allow yourself to become obsessed" 

"Picasso said, "The creative act is first and foremost an act of destruction" By destruction, we mean breaking a rigid set of assumptions about what can or cannot be done". Personally, I've always felt the process of creating was.. create, destroy, create, destroy, create. No single mark in a painting can be so precious that you would not be willing to sacrifice it to further the process of  painting. On a recent project, in selecting the art, we constantly re-evaluated the parameters we had set. When faced with a particularly challenging work of art we asked ourselves questions....Does it enhance the collection? is it appropriate for a healthcare environment? does it have a sense of transcendence? humor? is it a visual metaphor for the hospital experience? (and the more mundane... will it physically work in the space?) By taking this approach, we were free to evaluate every work of art, even artwork that would not traditionally be considered for a healthcare facility.
If you think of knowledge as "patterns of connections".  People apply their knowledge to the challenges and possibilities of the world around them. It gives you a "storehouse of relevant material with which to work, when faced with the needs of a wholly new solution. A motivated, curious mind, practiced in connection breaking, can escape inhibiting assumptions and make the subsequent connection to new ideas." But knowledge is a key component.

"Often when incompatible sets of information collide, we can ignore the new data in favor of old knowledge, replace old knowledge with the new, or find a third resolution. Evaluation is the last dynamic in the foundation of the creative process. Because choices are seldom cut and dried, fruitful evaluation is a balancing act." In this way, "using concerns arising in evaluation as focus areas for more creative work rather than as reasons to abandon the work, is critical to fully realizing a useful creative product. Allowing for this development to happen - providing the time necessary to multiply, reinforce, and verify new connections until they fulfill their promise - is the key to successful evaluation." This to me completely describes our art selection process, primarily our sculpture selection.